Seismic recording



March 1943- D. s. RENNER 2,313,091

SEISMIC RECORDING Filed Dec. 26, 1939 3 Sheets-Sheetl l i j lll llhDARWIN 6. RENNER Ailomeye.

7 March 9, 1943 s EN 2,313,091

SEISMIC RECORDING Filed Dec. 26, 1939 3 Sheets-Sheet 2 MRW/N 6. RENNB?Attorneys.

March 9, 1943. D. s. RENNER 2,313,091

SEISMIC RECORDING Filed Dec. 26, 1959 3 Sheets-Sheet 5 6PM (5. l'l

' seismic impulse.

Patented Mar. 9, 1943 UNITED sires orrt SEISMIC nnooanmc Darwin S.Banner, Dallas, 'leic, .assignor to Geophysical Service Incorporated, acorporation 01' Delaware 8Claims. This invention relates to improvementsin timing in an oscillograph recording with reference chiefly to theseismic method of geophysical prospecting, altho the invention is notconfined to this specific use.

In the seismic method of prospecting the practice of recording therespective phases of the seismic event has been to produce a record on amoving strip or tape of the instantoi the generatingimpulse, followed bya plurality of sideby-side traces of the seismic waves which arereceived at a plurality of points spaced from each other and from thepoint of initiation of the The recording camera. is so constructed thatthe record is marked oil in time intervals, the timinglines being spacedat the second intervals and every tenth line being modified wherebysecond intervals are readily determined. a

In this practice the completed record is manually given numericaldelineations, that is the lines are counted and marked with pen and ink.In cases where the zero mark, or the instant of creation of the seismicdisturbance, as by the detonation of an explosive charge in the earth,does not fall upon a timing line, a small time increment must be read tothe zero timing line and this timing increment will enter into everyreading taken from the record. This procedure is laborious andtimeiconsuming and offers possibility for error.

The present invention" contemplates method and apparatus whereby thereis produced an osciilographic record of a vibratory event, which recordincludes the exact timing from zero or the initiation of the event andwhich also includes a numerical chart from that instant, or any otherpredetermined instant, so that manual delineation of the timing lines isunnecessary.

It is the primary object of the invention to provide method andapparatus whereby there is provided an oscillographic record of .avibratory event, such record including a numerical scale beginning at apredetermined instant relative to any of the respective phases of theevent.

Another object is to provide; in addition to the usual timing lines'onan oscillographic record, a numerical chart beginning at any desiredpredetermined instant.

- Another object is to provide a recording device which includessynchronized mechanism for producing a numerical timing, chart upon therecording tape.

Still another object is to provide a seismic prospecting system wherebythe operation of the rerecord is directly related to the initiation ofthe cording mechanism is coordinated with the 'c'rea tion of the seismicimpulse so that the timing seismic event.

Further objects together with the foregoing objects will become apparentfrom the iollowing description of an embodiment of the invention, suchdescription being taken in connection with the drawings in which:

Fig. l is a diagrammatic illustration of a sys-' tern constituting anillustrative embodiment of the invention;

Fig. 2 is a diagrammatic view which illustrates one type of mechanismfor producing a'nu'merical chart upon the recording tape of anoscilliaph;

Fig. 3 is a plan view of a recording strip show ing the timing lines andnumerical chart thereon;

Fig. 4 is a side view taken at right angles to the cooperating elementsoi. the chart producing mechanism of Fig. 2; t

Fig. 5 is similar to Fig. 4 but taken on a horizontal line thru chartrecording elements;

Fig. 6 is a diagrammatic view which illustrates another form ofmechanism for producing timing lines and chart numerals.

Fig. '7 is a composite diagrammatic illustration showing the cooperativerelationship of the component parts of the system of the invention.

. Referring first to Figs.6 and '7 of the drawings there is shown atiming member i upon shaft 2 driven at a timed speed as by a constantspeed motor 8. This arrangement has above been referred to as previouslyused to produce timing lines 4 by the passage of spokes or radial bars 5thru a beam of light which passes thru lens 6 from the light source I.The cylindricallens 8 causes the' shadows of the spokes 5 to be cast insharp outline upon a sensitized strip or tape 9 moved at a uniform speedin the direction of the arrow 10. The member I is provided with anysuitable number of spokes and is shown by way of ond intervals by theremaining spokes which produce the lines t.

The present invention contemplates the additional use of a secondrotating member 15 which is driven .in synchronism' with the member I sothat the numerals l6 attached to the ends of the spokes I! movesuccessively into position at the end of the spoke I I which isforeshortened so that the shadow of the numerals successively producethe numerals I8 upon the moving strip 9. It is understood of course thatthe ratio of rotation of the wheels I and 1 is l/n where n is the numberof spokes in the wheel I5.

In order that the timing lines 4, l2 and I3 shall have a definiterelation with the respective phases of the event recorded upon the tape9, a systemsuch as that shown in Figs. 1 and '7 is provided. This systemcomprises a recording station 2% and a shot point station 2|, suchstations being interconnected as by a conductive line 22.

The recording station 20 comprises a timing mechanism of the type justdescribed and includes a number bearing wheel 30 adjacent which is acommutator 3i mounted upon a suitable support to which it is secured asby a screw 28 and slot 29 connection'as shown in Fig. 7. The commutatorSt has angularly spaced contacts 32 and 33 which are adapted to beengaged by a brush 3d rotating with the wheel 30. This wheel is shown asprovided with forty spokes so that the numerical chart will becontinuous for four seconds, a sufficient time for recording most phasesof a seismic event in geophysical prospecting.

The brush ea isconnected to the positive terminal of a battery 35 ofwhich the opposite terminal is connected thru relay 36 and resistor 3'!to the contact 33 on the commutator. The ne ative terminal of thebattery 35 is also connected to the negative terminal of a battery 38 inthe line 22, to the positive terminal of a biasing battery fill and tothe cathode M of a thermionic relay $2. The resistor 53 is connected tothe negative terminal of the battery Aid and has its opposite endattached to the grid id of the relay 32 and to the contact 32 on thecommutator iii. The plate 35 is grounded thru a manually operable switch36.

To provide telephonic communication between stations 2d and El,telephone equipment generally referred to as 50 and 58 is provided, the

earth being utilized as a return line.

At the station iii the line 22 is also connected 34, also driven by themotor, engages the contact 33. This closes a circuit from the battery 35thru the energizing coil of the relay 36 whereby the pilot lamp 39 islighted.

As soon as the pilot lamp 39 is lighted the operator at station 20closes the switch 46 and at the same time initiates operation of thetape driving mechanism. Hence as the brush 34 approaches contact 32during its rotation indicated by the arrow all parts of the recordingmechanism are in operation.

The thermionic relays 42 and 65 may be ordinary vacuum tubes biasedbeyond cut-off by the batteries 30 and ill or may be any of a number ofgas tubes which are rendered non-conducting by a proper grid or controlpotential. The relay 55 performs the same function as relay 32 but mustbe capable of conducting sufficient current to set off the cap for theexplosive 69.

When the brush 34 engages the contact 32 the grid it becomessufiiciently positive for conducto one of three terminals 52, 53 and 5cof va manually operable switch 55 comprising a housing 58 within which amovable assembly 5? is normally arranged upwardly by means ofcompression springs 58. The assembly 5? may hence be manually forceddownwardly by means of force applied to the handle 5E3 to bring theterminals 52, 53 and 5 into engagement respectively with stationarycontacts 6| $2 and 63 within the housing 53.

The contact Bi is conductively connected to the grid 56 of a thermionicrelay 55 and to one terminal of a resistor 56, thence to a battery 67 ofwhich the positive terminal has a common connection to ground, plate 68of the relay b5, and one terminal of the explosive mechanism 59. Theother terminal of the explosive mechanism is connected to the stationarycontact 63 of the switch 55. I

A battery 70 is used as a source of energy for setting .01? the cap forthe explosive 69. This I battery is connected thru a resistor H to thecontacts 53 and 54 of the switch 55, a capacitance I2 shunting thecircuit thus formed.

In the operation ofthe construction thus far described the operators aremutually advised that the equipment is ready for operation. The

switch 55 is then held closed-by pressure applied to the handle 60. Themotor 3 driving the timing wheels is placed in operation and the'brush.

tion and the resulting plate current which flows from the battery 38thru the line 22, the switch 55 and the resistor 56 similarly affectsthe'relay 55, whereupon the charge on the condenser I2 is instrumentalin setting off the explosive 69. The condenser M then recharges thru theresistor H but the constants of the system are so related that only asingle impulse is produced while the brush 34 passes over the contact32. This condition may be assured by providing a capacitance 63 betweenthe grid and ground as shown in Fig. 7 and such added element may befound necessary if the relay M is a gas filled tube.

The commutator 3i is angularly. adjustable as already indicated so thatthe instant at which the seismic impulse begins can be accurately set atzero for the area under observation and in this manner it is unnecessarywhen reading the record tomake any compensation for an increment of timebetween the creation of a seismic impulse and the beginning of. a timingchart on the tape 9.

A modified construction for providing the numerical chart together withthe timing lines on the recording strip 9 is shown in Figs. 2-to 5. Inthis construction a timing wheel such as that shown at l in Fig. 6 isused and is supplemented by a mechanism for applying the numbercharacters on the record. This mechanism comprises a character wheelmounted on shaft 15 and having openings it in which are mountedtransparencies bearing the desired numerals.

The wheel '15 is driven at a constant peripheral speed, together with ashutter wheel l1, mounted on'shaft ill by means of the shaft 18 drivenby any suitable source.- Hence at desired intervals the openings '89 inthe shutter wheel comelinto mating relation with the openings 18 of thecharacter wheel so that a light beam from a lamp is permitted to passthru the lens 8| and impinge upon a reflector 82 to reflect the image ofthe character upon the tape 9 whereby the desired numerical chart isformed.

It is believed apparent that numerous departures may be made from thespecific construction and technique above described. For example theinvention is not confined to the use of the brush and contactarrangement 3| to 34 but may, if desired utili'ie known expedienciessuch as the photo-electric cell for carrying out the desired functions.

Broadly the invention comprehends method and apparatus for providingoscillographic records having timing lines-and a numerical chart, therebeing a definite relation of the chart with the predetermined phase ofthe recorded vibratory event.

What is claimed is:

1. In the art 01' seismic prospecting the method comprising the stepsof. creating elastic waves in the earth, recording the instant ofcreation of the waves and the waves transmitted through the earth to apoint in spaced relation with the wave source, and simultaneouslyrecording a numerical chart of time of the seismic event such charthaving a predetermined relation with a definite phase of the event.

2. In the art of seismic prospecting the method comprising the steps oi,creating elastic waves.

in the earth, recording the instant of creation of the waves and, inside-by-side relation, the waves transmitted through the earth to aplurality of points in spaced relation with the wave source, andsimultaneously recording a numerical chart beginning at a predeterminedtimed relation with the initiation of the seismic waves.

3. The method of recording vibratory events comprising the steps ofcreating vibrations to berecorded, detecting said vibrations astransmitted to points spaced from the source, converting the detectedvibrations into electrical impulses, recording said impulses, andsimultaneously recording the instant oi creation of the vibration andtiming lines marked numericaily from such instant.

4. In the art of recording the creation and transmission of elasticimpulses, the method comprising the steps of creating elastic impulsesto be recorded, detecting and converting the transmitted impulses intoelectromotive forces in sympathy with the impulses, recording theinstant creation of the impulses and the transmitted impulses, andsimultaneously recording a numerical chart whereby the sequence and timerelation of the series of events is determined.

5. In the art of seismic prospecting the combination of, means forcreating elastic waves in the earth, means for recording the instant ofcreation of the waves, means for detecting'and recording the wavestransmitted through the earth to points in spaced relation withthe'waves and means for simultaneously recording a numerical chart oftime of the sequence of events.

6. In the art of seismic prospecting the combination of, a-source ofseismic waves, means for producing a continuous record including theinstant of initiation of the waves by said source and the arrival of theresulting waves at points in spaced relation with the source, and meansfor simultaneously producing upon said record timing lines and anumerical chart, said last mentioned means being operable at apredetermined instant relative to the sequentially recorded events.

'7. Seismic prospecting apparatus comprising, a shot point station and arecording station in spaced relation, a source of elastic waves at theshot point station, and means at the recording station for energizingsaid source and for simultaneously recording the shot instant andproducing a numerical time record from that instant.

8. Seismic prospecting apparatus comprising, shot point and recordingstations in spaced relation, means for transmitting energy therebetween,a source of elastic waves at the shot point station, means forenergizing said source, means for producing a record of'the shotinstant, and means for producing a time chart beginning at apredetermined phase oi the seismic event created by the source. a

DARWIN S. RENNER.

